In the circuit shown, X is joined to Y for a long time and then X is joined to Z. The total heat produced in R₂ is

 

Two different coils have self-inductances L₁ = 8 mH, L₂ =2 mH. The current in one coil is increased at aconstant rate. The current in the second coil is also increased at the same rate. At a certain instant of time, the power given to the two coils is the same. At that time the current, the induced voltage and the energy stored in the first coil are i₁ V₁and W₁ respectively. Corresponding value for the second coil at the same instant are i₂, V₂ and W₂ respectively. Then